Means for strengthening weak electrical impulses.



W. SCHLOEMFLCH & A. LEIB. MEANS'FOR STRENGTHENING WEAK ELECTRICAL IMPUL'SES,

APPLICATION FILED APR.15. 1913 Patented Dec. 7, 1915.

3 SHEETSSHEET I.

w. SCHLOE-IVIILCH & A. LEIB.

MEANS FOR STRENGTHENING WEAK ELECTRICAL III'IPULSES. APPLICATION FILED APR. I5. I9I3.

LIE 180, I Patented Dec. 7, 191.5.

3 SHEETS-SHEET 2.

M f z 7 W. SCHLO'EMILCH: A. LEIB. MEANS FOR STRENGTHENING WEAK ELECTRICAL IMPULSES.

' APPLICATION FILED APR. 15 I913 v r Llgjfl, Patented Dec. 7, 1915.-

3 SHEETS- SHEET 3.

Ann?!" Ll63Jl8ll. Original application filed .lune 16, 1910,

qth e following is a specification.

- ture. possible to produce in the local circuit ma- 7 vvrrnnmvr scnnonlvrrrcn Ann Aueusr LEIB, on BERLIN, GERMANY, nssreivons ro GnsnLLscHarr runn nnnn'rnosn 'rnnncnnrnin in; e. 3., or BERLIN, GERMANY.

lunans iron srnnnernnlvnvc vvnnir 'nLnc'rnIcAr. nurunsns.

Specification of Letters ratent.

I Patented Dec. v, leis.

' 1913. .SerialNo. 761,317.

useful Improvements in Means for Strengthening Weak Electrical impulses, of which 'The present invention relates to means for ,-strengtl 1ening weak electrical impulses which tmay be of an irregular kind, suchfas frequently occur, for example, in receiving stationsforradiotelegraphy,or also for example, in ordinary telephony along continuous lines.v f t According to the invention the Weak'impulses act on a relay, whose armature is damped very little acoustically and coiiperates with a granular contact of the type customary in microphones located in a local circuit. The one electrode of the granular contact is firmly connected with the-arma With the aid of these means it is terially greater fluctuations of current than the primary, weak impules acting on the relay.

The present application which is divided from our co-pending application Serial No; 567,208, filed June 16, 1910, covers certain.

features more particularly embodied in Figures 13 of aforesaid application. For the sake of a clear understanding of our invention we have embodiedthe specification of aforesaid application in substance in the present one.

It 's Well-known, for the purpose of strengthening weak impulses to allow the same to act on a relay whose armature 006perateswitha microphone contact in a local circuit. In the arrangements ofthis kind, known heretofore, however, either the armature of the relay is'very highly damped so that it possesses no. sharply-defined natural vibrations, or the microphone contact was not. formed as a granular contact, or there.

was no fixed connection between the armature and the one electrode of the granular contact. For obtaining the effect aimed at by the invention, it. is essentiahhowever,

that the armature be damped very little,

acoustically and consequently possesses a sharply defined natural vibration and is simultaneously combined in the manner in.

thousand fold 'vveak which have ,been scarcely perceptible here- I: dicated With a gran'ular contact. Preferably means-are provided which enable the armature to. be tuned to a definite period of vibration. Y V

For optionally strengthening the arriving I I impulses it is necessary to connfict in series by, 'Way of the granular contacts several such strengthening relays by connecting in Serial'No. 567,208. Divided and this application filed April 15,

the contact-circuit of the first strengthening relay a secondfstrengthening relay, and in the contact-circuit of the second strengthening relay a third relay, and soon. In this manner it is possibleto strengthen. many electrical impulses tofore by means of'a telephone placed close to theear and to make them perceptible at many meters distance by means of a socalled loud talking telephone.

If regular impulsesare operated with, as

is generally customary in radiotelegraphy, all the oscillating armature systems are preferably tuned to the periodicity of the ar-' rivin'g fluctuations of current. lf continuous or approx mately continuous impulses or successionsof lmpulses which are outside the range of the acoustic vibrations per-- ceptible by the human ear or are irregular are operated with, it is preferable to com- Also a is possible to record or indicate such weal:

bine the receiving circuit also with a rectifier and a device for periodically varying the vibrations, in which event the last-mentioned device is tuned to the period of vibration of the armature systems of the strengthening relays.

'lhe contact-circuit or local circuit of the last strengthening relay may be connected With a telephone, horn-or the like, or, in the event of the arriving signals having to be recorded, with a suitable recording apparatus, such as a Morse recorder, siphon recorder, galvanometer, incandescent lamp in the latter case it 15 preferor the like. able not to connect the recording apparatus directly with the last local circuit but by means of suitable devices, which keep oh. from the recording apparatus or the relay used for working the same the closed cir cnit current which flows in the last local VT 7 aeaiao circuit and is frequently subjected to disturbing variations. To this end, a vibration'relay or a transformer or a similarly acting. device may be provided which has the efiect solely of transmitting the fluctuations of current, produced by the last strengthening relay, in the last local circuit to the recording apparatus or its driving relay, and stopping the passage of the closed circuit current. When employing a transformer for the above purpose, it is preferable to interpolate in the secondary circuit of the same a rectifier which converts the alternating currents in the secondary circuit into direct ourrent impulses. The contact detector, such as a granular contact, thermo-electric cell etc.. customary in radiotelegraphy has proved particularly suitable as rectifier for these relatively slow alternating currents.

' The constructional form and mounting of the strengthening relay and its oscillating armature system is also of great importance for carrying the pre'sentinvention into practice. In the tests made in this direction, one definite mounting of this system,

one definite form of the granular contact,

\ and one definite insulation, regulation and mounting of the relay have proved particularly suitable, which will now be more particularly described with reference to the drawings. n

Several illustrative embodiments and de tails of the inventionare represented diagrammatically as an example in the accompanying drawings, wherein:

Fig. 1 shows a receiving connection for tradiotelegraphy; Fig. 2 shows a modified mode of connecting a recording apparatus with the local circuit of the laststrengthening relay; Fig. 3 shows a receiving connec- 7 tion which s particularly suitable for receiving continuous or approximately con tinuofis oscillations; Fig. 4 is a cross-section through a strengthening relay, and Fig. 4 is a detailof the latter; Fig. 5 shows the mounting of the oscillating system of the strengthening relay, and Fig. 6 the suspension of the strengthening relay. Fig. 7

represents a portion of the arrangement shown in Fig. 1 with the addition of acutting off device for the relays. v Referring'firstly to 1, a designates the earthed receiving aerial containing the condenser f is in parallel with The strengthening relay 0Z self-induction coil Z), A- circuit branches ofi from this coil, in which circuit is interpolated a rectifier a and the strengthening relay (Z. In ithe'illustrative embodiment an electrolytic detector, such as is customary in radiotelegraphy, is used as rectifier. A the relay. has an armature g which is damped 'very little acoustically,

is preferably carried by a vibratory system stretched between two opposite points, and

cooperates with the granular contact 5 The latter consists of the fixed carbon electrode a and an. electrode opposite it secured on the armature. Both'electrodes are connected one with the other at their edges by a very thin flexible tissue so that a chamber, which is filled entirely or partially with grains of carbon, is formed between the electrodes. Thus the contact substantially corresponds' with the granular contacts customary in microphones.

The impulses received by the receivingaerial are conducted by way of the rectifier c and the condenserf and converted into direct current. impulses which act on the strengthening relay d. The latter imparts the impulses by means of its but little damped armature to th'egranular contactwhich is interpolated in a local circuit Z containing the source of current k and pro duces in this circuit fluctuations of current which are materially strengthened as compared with the weak primary fluctuations.

For strengthening the impulses still more, it

is preferable to connect a plurality of such strengthening relays in series by interpolating a second strengthening relay d in the '10- cal circuit Z of the first strengthening relay,

and arranging a thirdstrengthening relay (l in the armature circuit Z of this relay, and so on. The l ocal circuit of the last strengthening relay may be connected by means of the change-overswitch we either with the telephone n or with a suitable recording apparatus 0. .The weak fluctuations of current received by the receiving aerial are strengthened by these means to such an extent that the fluctuations can be made acoustically perceptible by means of the telephone a at many meters from the telephone. lif the strengthened impulses of currents are allowed to act on a recording apparatus it is preferable to connect the last local cirdirect current relay 0 whose armature circuit 0 contains the'recording apparatus 0, is in parallel with the contact. p 12 Aslongas no fluctuations occur, the direct cur- Y rent relay 0 remains currentless because it is short-circuited by the contact 9 10 But as soon as the armature system 10 vibrates, the contact between 79 and p is practically open and the direct-current relay is actuated. The purpose ofithe resistance {0 is rent flowing in the recording apparatus o or from the trancmission relay .0 provided for driving the same. If the fluctuations of current in the last local circuit are allowed to act directly on the indicating device or on the tI'flIlSIIllS sion relay, the. defect is met with that, the

action offtheindicating apparatus is fr'ef-lquently subjected to disturbances. These disturbances are due to the "strongclosed circuit current disturbing influence of the granular. contact or to the occurrences in the contact vibrations relay, p the closed circuit current from the transmission relay 0' and only the fluctuations of current produced in the loc'alcircuit by the strengthening relay are tran'sc mitted to the relay o also he obtained The same action can granular contact it is in the circuit 'of the last local circuit Z containing the'source of current k lln-thislocal circuit is interpolated the primary coil of a transformer at, whose secondary coil is connected witha rectifier M and the direct-current relay 0 The condenser u is in parallel with the.

relay 0 The armature of this relay serves for opening and closing a local circuit 0 in which the indicating device 0, such as a siphon recorder, relay and bell, Morse apis interpolated.

. in the local circuit Z by the strengthening relay d"? are superposed on the closed circuit current which proceeds from the battery 10%.; As the transformer u only transmits theseiiuctuationsof current, the closed I circuit currentand the disturbing variation of the same is kept awayfrom the direct current relayo a The alternatecurrent irnpulsestransmitted by thetransformer to the secondary circuit, are converted by the rectifier a into direct cui'rent impulses which are then supplied to -the-relay 0' in all cases an ordinary contact detector can be used as rectifier, such as is frequently employed for rendering electric oscillations perceptible in radiotelegraphy. Instead of I the transformer at having two.-coils, a so "called auto transformer having only one coil could he used.

The fluctuations of current are strength ened lparticularly W in the local circuit 1 is kept away" by thearrangement of a transformeras shown in Fig. 2. .Here 01 shows-the last' strengthening relay, whose;

I .IfLfcontinuous or, approximately continu- 7 well when the maximum strength of current in the individual local circuits and, correspondingly, the quantity and size ofgrains-ofthe individual granular contacts are selected corresponding to their order, so that thequantity of grains in the contact 71. is larger than thatinthe contact 7L and that in'the contact h is larger than ,that in contact 71.

The strengthening of current is likewise a-ll the greater,the better the fluctuations of the individual armatures are tuned one to another." If the first strengthening relay (Z -has supplied to itacurrent whose number ,:of impulses is, say'gof the order of acoustic. ,vibrations perceptible by the human ear,

which is; the ease for example, when oper: ating with singing sparks, according 'to'thc armaturesf-of the strengthening relays. are

not only itunedonetoanother, but also to thenumber of impulses to be strengthened.

this event the efi'ec t of the arrangement is particularly.favorable. If the current in1-, uses which ar'eto'be strengthened are not gularjbutirregular, as is the case in thetelephonic transmission of speech, it is preferable to make the-natural vibrations of the "methOdQwell-knoWn in radiotelegraphy, the

armature "higher than the most rapid im- 7 ulseifof' thetelephonic current which is to bestrengthened;

oust oscillations are, operated with in radiotelegraphy,'orif impulses whose frequencies are outside the'range of the vibrations perceptable-by the human car are worked with,

or impulses which follow one another irregularly, the receivingconnection represented inhig. 3 is preferably employed, in which the'rectifier c interpolated in the receiving circuit co'ope'rates'with a device a for periodically varying the vibrations. This device may be an; automatic interrupter, 6. 'g.- a so-called ticker, such as isalready employed in'radiotelegraphy when receiving non-damped oscillations. Such an interrupt'er having a rotating contact wheel is representedin the drawing. The continu-- ous or approximately continuous oscillations received byfithe receiv ng aerial are converted by the rectifier 0 into redressed curreceiving aerial are supplied only by way of it,-'5-. e. after periodic variation to the rectifier c. Preferably a condenser is connected in parallel with the rectifier insuch manner is then discharged through the interrupting device 42 in proportionto its number of inthat the received energy redressed by the rectifier 0- is stored up in the condenser. This storage also takes place while the interrupter v is being opened. The condenser terruptions and independently of the sequence of impulses of the direct current can be moved in the neck of the bow r and can set in every position by ascr'ew T The movable electrode is formed'by the araround the rollers 8 s from the attachment pin 8 by way of the mature g of the electro-magnet, which will be referred to hereinafter in detail. The

contact face of the fixed electrode is prefers ably sloped so that a downwardly-enlarging space or chamber is formed for receiving the contact grains. Also, the electrodes are preferably arranged in such manner that the chamber for 'the grains is vertical, in

order in this manner to diminish as much as possible the load on the armature due to the grains and, consequently,- the dampi ng of.

the armature.

The crossbar r 'fadjustable relatively to the magnet serves simultaneously as support for the vibrating. armature system. As Fig. 5 shows, this is formed by a wire system, to which the armature issecured in. suitable manner.

I Preferably one single wire s is employed which is guided in a loop The wire passes roller 8 to the second attachment 'pin 8.

The armature g-is secured on the wire loop between the rollers s and s -pose of tuning the armature system the For the purroller 8 is held bythe bearing 8 movable in the direction of the roller 8 andconnected with a screw 8. The latter passes through an internally-threaded member fixed on the frame of the case and in this manner enables the wire loop to be tensioned. The wires of the wire system-are arranged par-' allel to the line connectingthe centers of the faces of the magnet poles, and the armature 9 may not be materially broaderv than the pole faces opposite it. In this manner itisobtained that the two wires participate to the same extent and in the same sense in the vibratory movement and thearmature does not tilt toward the magnet when it moves. @bViously, the wire could be arranged and secured in another manner than that shown, and instead of the wire any other suitable member may be used for carrying the armature.

The principal feature of the arrangement of the present armature as compared with known arrangements consists in the armaor more plates 9 of cork or felt, but not by' screws or similar rigid members, but prefeably by an adhesive substance. The plate 9 is. secured by an adhesive substance on an ebonite plate t and this on the support 2?. To the same end, current is supplied to the relay by means of soft flexible conductorsm which do not conductithe sound, as eag. strands formed by plaiting a number of the finest copper wires, orslender metal ribbone," 6. g. tinsel.

- In order to keep away exterior sounds from the relay the same is preferably inclosedin a cork casing g and surrounded,

in addition, with a metal casing a, the purf pose of which is to keep off the relay electromagnetic oscillations which might act' directly from without on the relay. For regulating the sensitiveness of the relay there is arranged in a front chamber 2 of the metal case an annular magnet 2 (Fig. 4 which is j'ournaled concentrically on an axle and can be rotated by means of a button or milled head 2 By rotating the magnet .2, namely by changing the position of its poles relatively to the poles of the strengthening relay, the sensitiveness of the lattercan be regulated. a V

Now it has been found that in stations for radiotelegraphy the granular contacts are impaired when the contiguous transmitting circuit is closed for the purpose oftransmitting, because currents are induced in the local circuits Z Z l, which traverse the granular contacts and frit together the grains. This defect is in part remedied by the metallic case around the relay. For

completely remedying the same, it is preferable, however, to leadthe local circuits of the individual strengthening relays by way of special contacts which are opened automatically when a transmitting circuit is closed. This arrangement is shown in Fig.

7. In this figure, which in general arrange ment is the same as shown 1n. Fig. 1, on

either side of the granular contact device incense contacts 5 are closed.

' In order to protect the relay against me- "chanical shocks, to which the carrying frame 01 the relays is subjected, the relays are suspended cardanically, as shown in Fig. 6. As

this figure shows, a plurality of relays d 0?, are secured to a common carrier t, which issuspended movably toward all sides by means of a rod a portion of a sphere i and a bearing i A hollow indie-rubber ring distended by air or another elastic body is preferably placed betweeirthe portion of the sphere and the bearing in order to absorb shocks in a vertical direction from the relays and simultaneously to damp the oscillation of the relays.

I trodes and a granular contact therebetween,

We claim:

1. In an arrangement for strengthening weak electrical impulses, means for receiving weak impulses, a relay comprising an electromagnet and an. armature suitably supported so as to permit its swlnging freely with its own period, means for varying the period of the armature, two elecone of said electrodes being fixed to said armature and of small'mass to still permit the swinging of said armature with its own period, a rectifying device acted upon by the weak impulses, a device for periodically varying said weak impulses, the armature of said strengthening relay being tuned to the periodicity of the variation device.

2. In an arrangement. for. strengthening weak electrical impulses, meansfor receiving weak impulses, a relay comprising an electromagnet, an armature suitably supported so as to permit its "swinging freely with its own period, means for varying the 7 period er the armature, two electrodes and a granular'contact therebetween, one of said electrbdes being fixed to said armature and of small mass to still permit the of said armature with its own period, a recdenser adapted to. be charged by the rectitifying device acted upon by the weak 1m-' pulses, a device for periodically varying said weakimpulses, the armature of said strengthening relay being tuned to the periodicity of the variation device, and a confied currents and discharged by. the variation device, 3

3. The combination with an apparatus for perceiving and strengthening weak electrical oscillations, of means for converting the strengthened direct current impulses currents and a recording apparatus.

, 4:. The combination with an apparatus for perceiving and strengthening weak elec:

trical oscillations, of a transformer converting the strengthened direct current impulses into alternating currents, a rectifier for converting the alternating currents into directgcurrents and a recording apparatus.

5. llhe combination with an. apparatus for perceiving and strengthening weak electrical oscillations, of a transformer for converting the strengthened directcurrent impulses into alternating currents, a contactdetector of the character used for high frequency vibrations for re-converting the alternating currents into direct currents and a recording apparatus. 7

6. llhe combination with an apparatus for perceiving and strengthening weak electrical oscillations, of a transformer converting the strengthened direct current-impulses into alternating currents, a rectifier for reconverting the alternating currents into direct currents, a relay connected in series with said rectifier and the secondary winding of said transformer, a condenser in parallel with said relay, and a recording apparatus.

7. in an arrangement for receiving and strengthening weak electrical impulses,

means for receiving weak impulses, a relay comprising an electromagnet, an armature suitably supported so as to permit its swinging freely with its own period, a rectifying device acted upon by the weak impulses, a device for periodically varying said weak impulses, the armature of said strengthening relay being tuned. to the periodicity of the variation device, and a condenser adapted to be charged by the rectified currents and discharged by the variation device.

WILHELM SCHLOEMILGH. AUGUST LEIB.

Witnesses:

HENRY srnn, WOIDEMAB Ham-r. 

